Chebulic acid derivatives from Balakata baccata and their antineuroinflammatory and antioxidant activities

Sixteen chebulic acid derivatives, including nine new (1-9) and seven known (10-16) ones, were isolated from an ethanol extract of the branches and leaves of Balakata baccata. The structures of the new compounds were elucidated by their UV, IR, HRESIMS, NMR, electronic circular dichroism (ECD) and single-crystal X-ray diffraction data. The effects of all the isolates on antineuroinflammatory and antioxidant activities were evaluated. Compared with the positive control minocycline (IC₅₀ = 1.21 ± 0.71 μM), compounds 1-16 with IC₅₀ values being greater than 50 μM, displayed almost no effects on the inhibition of NO production in LPS-induced BV-2 microglial cells, however, the results of antioxidant activity for compounds 1-16 showed significant DPPH-radical scavenging abilities with EC₅₀ value ranging from 3.98 to 14.24 μM, while the EC₅₀ value of positive control vitamin C was 14.31 μM. At last, the results of PCR (qRT-PCR) analysis showed that compound 1 could enhance the expression of antioxidases (HO-1, GCLC, and NQO1) at the mRNA levels.